title: Aspirin use and risk for lung cancer: a meta-analysis.
abstract: BACKGROUND
  Aspirin has received increasing attention owing to its potential as a chemopreventive agent against lung cancer. Previous observational studies have reported inconsistent findings on this issue. We investigated the association between aspirin use and risk for lung cancer by conducting a meta-analysis.
  
  
  METHODS
  Relevant studies were identified by searching Medline, EMBASE, and Cochrane Library to December 2009. We also reviewed relevant bibliographies from the retrieved articles. Two authors independently extracted data and assessed study quality. Disagreements were resolved by consensus.
  
  
  RESULTS
  Fifteen studies (six case-control studies and nine prospective cohort studies) were included in the final meta-analysis. When all studies were pooled, the odds ratio (OR) of aspirin use for lung cancer risk was 0.86 [95% confidence interval (CI) 0.76-0.98]. In subgroup meta-analyses, there was no association between aspirin use and lung cancer risk among cohort studies (relative risk, 0.97; 95% CI 0.87-1.08), while there was a significant association among case-control studies (OR, 0.74; 95% CI 0.57-0.99). In a subgroup meta-analysis by quality of study methodology, a significant protective effect of aspirin use on lung cancer was observed only among eight low-quality studies (OR, 0.82; 95% CI 0.68-0.99), but not among seven high-quality studies (OR, 0.90; 95% CI 0.76-1.07).
  
  
  CONCLUSIONS
  Overall, the findings of this meta-analysis support that there was no association between aspirin use and lung cancer risk. Our findings should be confirmed in future prospective cohort studies or randomized, controlled trials.
authors.affiliation: Department of Family Medicine, Healthcare System Gangnam Center, Seoul National University Hospital, Seoul.
authors.forename: S-W
authors.initials: SW
authors.lastname: Oh
authors.affiliation: Cancer Epidemiology Branch, Research Institute, National Cancer Center, Goyang. Electronic address: msk@ncc.re.kr.
authors.forename: S-K
authors.initials: SK
authors.lastname: Myung
authors.affiliation: Department of Family Medicine, Kwangdong Oriental Hospital, Seoul, Korea.
authors.forename: J Y
authors.initials: JY
authors.lastname: Park
authors.affiliation: Department of Family Medicine, Healthcare System Gangnam Center, Seoul National University Hospital, Seoul.
authors.forename: C M
authors.initials: CM
authors.lastname: Lee
authors.affiliation: Department of Family Medicine, Healthcare System Gangnam Center, Seoul National University Hospital, Seoul.
authors.forename: H T
authors.initials: HT
authors.lastname: Kwon
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage*; D001241:Aspirin / Q000008:administration & dosage*; D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000453:epidemiology* / Q000517:prevention & control*; D008297:Male
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D001241:Aspirin